1. Field of the Invention
The present invention relates to a cleaning device for removing toner adhering to a moving body, and an image forming apparatus provided with the cleaning device.
2. Description of the Related Art
In image forming apparatuses such as copiers, printers, facsimile devices, and composite machines thereof, a moving body to which toner adheres is used. Examples of such moving bodies include a photosensitive body on which a toner image is formed, an intermediate transfer body to which the toner image formed on the photosensitive body is transferred, a transfer member that transfers the toner image having been transferred to the intermediate transfer body to a sheet in a transfer position.
It should be noted that no toner image is formed on the transfer member. However, when images are to be formed on both sides of a sheet, one side (surface) of the sheet on which an image has been formed in advance contacts the transfer member, and thus the toner on the surface of the sheet may sometimes adhere to the transfer member.
Toner remaining on the photosensitive body or on the intermediate transfer body after transfer of a toner image, or toner adhering to the transfer member is removed by a cleaning device. Such a cleaning device is disclosed, for example, in Japanese Unexamined Patent Application Publication Nos. 2007-72398 and 2009-36957.
A cleaning device disclosed in Japanese Unexamined Patent Application Publication No. 2007-72398 has a plurality of brush rollers that abut to the surface of an image carrier which is a moving body, and applies bias voltages having polarities different from each other to at least two brush rollers. Then, the surface velocity of a brush roller, to which a bias voltage having a polarity opposite to the normal charging polarity of the toner, is applied, is set to be quicker than the surface velocity of a brush roller, to which a bias voltage having the same polarity as the normal charging polarity of the toner is applied.
A cleaning device disclosed in Japanese Unexamined Patent Application Publication No. 2009-36957 includes a first brush member, a second brush member, and a third brush member that respectively contact the surface of an image holding member which is a moving body. The second brush member is arranged on the downstream side of the first brush member in the moving direction of the image holding member, and the third brush member is arranged on the downstream side of the second brush member in the moving direction of the image holding member. Then, to the first brush member and the second brush member, bias voltages having different polarities are applied, and the mechanical scraping force of the third brush member is made stronger than mechanical scraping forces of the first and second brush members.